The tail section of the AirAsia plane that crashed into the Java Sea has been raised but Indonesian investigators did not find the black box recorders inside.

A metal section with the words "AirAsia" visible across it was brought to the sea's surface on Saturday using floatation devices.

The aircraft carried the cockpit voice and flight data recorders -- or black boxes -- near its tail. Their recovery is key to learning why the plane crashed on December 28, killing all 162 people on board.

Searchers detected ping signals from the black boxes of Flight 8501 on Friday, but officials said the boxes seemed to be separated from the tail section.

The tail was located Wednesday on the sea bed at a depth of around 30 meters about 30 kilometers from the plane's last known location.

The Airbus 320 vanished from radar screens over the northern Java Sea less than halfway into a two-hour flight from Indonesia's second-biggest city of Surabaya to Singapore.

Forty-eight bodies have been recovered so far.

Authorities hope most of the rest of the victims can be recovered from the several large pieces of wreckage that have been detected on the ocean floor.

Before takeoff and during the last moments of the flight, the pilots requested to fly at a higher altitude to avoid a storm. The request was not approved because other planes were in the area.